Slowing down film after shooting

[chooser]

have shoot a mos scene at 24fps, looking at the footage now, with hind sight should have shot at a higher frame rate. what is the best way to slow it down to 48fps or 50% speed reduction. do i just note it for the neg cutter and lab? in fact there is probably a number of short mos takes that would work better slower. basically any info on this would be appreciated .. thanks

[Chris Keth]

have shoot a mos scene at 24fps, looking at the footage now, with hind sight should have shot at a higher frame rate. what is the best way to slow it down to 48fps or 50% speed reduction. do i just note it for the neg cutter and lab? in fact there is probably a number of short mos takes that would work better slower. basically any info on this would be appreciated .. thanks

<{POST_SNAPBACK}>

 

 

Well, if you really, really want to, you could probably optically print it so you print all of your frames but between each one kind of interpolate what the middle frame would have been, but that's a ton of work.

 

You could also get passable results by doubling each frame, essentially getting the same thing as when an animator shoots on twos.

[David Mullen ASC]

Once again, is this project for PRINT or for video-post ONLY?

 

I can't get why people don't seem to think this bit of info is relevant!

 

I'm going to assume that since you said "negative cutter" that this is for print. So the next question is: was this shot in 16mm? Is this for a blow-up to 35mm? Or is this just meant for contact-printing?

 

And why is this question in the Cinematographers category, usually used to discuss cinematographers?

[chooser]

if I was going to DVD or digi I would not be be asking the question, since I actually do that for a living. It was shot 35mm and obviously if a "neg cutter" is involved there must be a print involved.

 

if this is not the right forum more than happy to post it else where Mr Mullen ... just let me know which forum you feel is best. don't want to blurr the lines between "departments"

Edited January 19, 2005 by chooser

[Thomas Worth]

Wow Dave, when was the last time you got dissed in public like this? Dude, you should be grateful that "Mr. Mullen" is even responding to you. Learn some respect!

[Dominic Case]

do i just note it for the neg cutter and lab?

"Just noting it" for the neg cutter won't do it. You will need to have that shot extracted and sent to the lab for an optical (or digital optical) before the actual neg matching begins.

 

For a 50% slow-down, optically it could be straghtforward frame doubling (stretch printing). Digitally it might be possible to go through a frame interpolation process which would smooth out the movement considerably: it's a question of which effect you want.

 

There is a half-and-half alternative, also an optical effect: the "inbetween" frames consist of a double exposure: 50% of the previous frame, 50% of the following frame: so in effect each original frame is seen to fade in and out, overlapping with the next by one frame. It's a little smother than simple frame-doubling, but isn't interpolating in any way.

 

Whichever method, you will get back an optical/digital dupe neg which has to be cut in with the rest of the original neg.

 

Without wanting to wade into "category wars", this doesn't really belong here in "cinematographers", which is about the people and their craft. "35mm only" is where I would have put it, as there isn't a category for "post" other than "film stocks and processing". But it's here now.

[chooser]

thanks for the reply dominic. appreciated. and no thomas, its not a "diss" as you put it but a genuine question like the original one. i will be a little more careful when selecting forums to post in future, as i do not want to step on anyones toes here. i like everyone else appreciate mr mullens advice. thankyou.

[John Sprung]

Digitally it might be possible to go through a frame interpolation process which would smooth out the movement considerably: it's a question of which effect you want.

 

There is a half-and-half alternative, also an optical effect: the "inbetween" frames consist of a double exposure: 50% of the previous frame, 50% of the following frame: so in effect each original frame is seen to fade in and out, overlapping with the next by one frame. It's a little smother than simple frame-doubling, but isn't interpolating in any way.

<{POST_SNAPBACK}>

I've seen the double exposure thing tried for going from 48 fps photography to 24 fps projection with the hope of making normal motion. Each frame of the print consisted of two OCN frames double exposed. It really didn't work at all, because you see the double images on anything that moves. For instance, my hand would have 5 fingers when stationary, but 10 fingers if I move it.

 

Going the other direction, making two copies of each frame would give you 12 fps, and the equivalent of a 90 degree shutter, which is below the threshhold of the illusion of motion for most people. I wonder if the double exposed in-betweens would show up as double images, given that you see them every other frame. My guess is that they would. My experience with printing to change speeds is that you see what's actually on the frames.

 

As for digital frame interpolation, I've never seen it done successfully. It would require automatic object recognition, and nailing that would solve the fundamental problem of robot vision. It'll be very interesting when it happens.

 

 

 

-- J.S.

[David Mullen ASC]

The most common approach for a project meant for printing is to use an optical printer. You remove that piece of negative from the camera roll, get an IP made, this gets loaded into an optical printer, and a new IN is made where every original frame is printed twice on the IN. (I'm skipping the wedge-testing usually done to choose color balance).

 

This IN is then cut into the conformed original negative.

 

If this was a blow-up from 16mm to 35mm, you could blow-up the 16mm neg of that shot to a 35mm IP and then to a 35mm IN -- I assume you could do the double-frame printing either when making the IP or in the IP-to-IN step. Then the finished effect would be cut into the blown-up 35mm IN of the whole film. In this way, the double-printed shot would be the same generation as the rest of the blow-up.

[Dominic Case]

thanks for the reply dominic. <snip>

i like everyone else appreciate mr mullens advice. thankyou.

 

Hey, why do I get "dominic" and david gets "mr mullen"? Let's have a little respect here. B) Just 'cos he's ASC doesn't mean he's a knight of the realm or anything. He's entitled to first name recognition too :blink:

 

Seriously, Mr John Sprung says

I wonder if the double exposed in-betweens would show up as double images

. Well, probably a bit more than 2/3 pull-down on NTSC transfers does: as every other frame there consists of two mis-matched fields.

 

David Mullen's description of the optical printing process makes it very clear. This has been used for the past 75 or more years without a lot of debate or agonising over it.

[David Mullen ASC]

Hey, why do I get "dominic" and david gets "mr mullen"?

<{POST_SNAPBACK}>

 

I feel too young to be called "Mr. Mullen" -- that's my Dad.

[chooser]

I would like to thank Mr Mullens, Mr Case, Mr Worth, Mr Sprung and Mr Bunnies. I would also like to thank David, Dominic, Thomas, John and er Mr Bunnies. And of course all the other kind members of the cinematographer.com academy and members of the foreign online forum press association ... and my mum.

Edited January 20, 2005 by chooser

[John Sprung]

Well, probably a bit more than 2/3 pull-down on NTSC transfers does: as every other frame there consists of two mis-matched fields.

<{POST_SNAPBACK}>

Well, actually, NTSC doesn't show you frames. Come to think of it, neither does PAL or SECAM. Interlaced video systems show you one field at a time. With 3-2 pulldown, NTSC shows you three fields taken from one frame followed by two fields taken from the next frame. You never have two different temporal samples presented on the display at the same time.

 

Double exposing consecutive frames in a film printer does give you two different moments in time presented at once. If you move your hand at the right speed, those double exposed frames will all show a ten fingered hand when viewed one by one as stills. Project it it motion, and you get exactly the same thing, a ten fingered hand.

 

NTSC with 3-2 converts smooth constant motion to a rapid sequence of speed ups and slow downs, but it never gives you double images.

 

 

 

-- J.S.

[Dominic Case]

Well, actually, NTSC doesn't show you frames.

Fair point, John.

 

I did a demo if the method I described some years ago, using a clock leader to explain it. Although in fact, it was a slightly more complex stepping pattern, designed for an archive to stretch 16fps material for projection at 24fps. (More of a waltz than a two-step!). It seemed to me that it jittered less than the conventional double printing of every alternate frame. But of course there is no motion blur (nor do you expect any) in a clock leader, so it's not a fair subjective test.

 

I don't think many people have ever bothered much with these double image methods. As I said, simple repeat frame printing in an optical printer has been OK for long enough.

[Chris Keth]

Shooting on 2s is very common to do when animating, I don't see why it shouldn't work fine here.

[Glenn Hanns]

If your going the digital route theres a need plugin for combustion, AE and Apple Shake called Twixtor that will intelligently interpret between frames.

LINK

[Allen Achterberg]

If your going the digital route theres a need plugin for combustion, AE and Apple Shake called Twixtor that will intelligently interpret between frames.

LINK

<{POST_SNAPBACK}>

 

 

yeah I use that, its aight. I use it to go 60i-60P-24P as well, does a decent job, It looks just as good as the job done on open water. less artifacting actually.

[John Sprung]

Shooting on 2s is very common to do when animating, I don't see why it shouldn't work fine here.

<{POST_SNAPBACK}>

The difference in animation is motion blur. Animaiton is a very "hand-made" kind of thing, you can make whatever it takes to get the blur you want. In the case of the original question, he'd have 12 fps and the equivalent of a 90 degree shutter, which is too sharp to look like motion.

 

 

 

-- J.S.